class monkey {
    void crySpeak(String s) {
        System.out.println(s);
    }
}

class People extends monkey {
    void computer(int a, int b) {
        int c = a * b;
        System.out.println(c);
    }

    void crySpeak(String s) {
        System.out.println("刘雨坤" + s + "刘雨坤");
    }
}

public class zoo {
    private static Object monkey;

    public static void main(String args[]) {
        People geng = new People();
        monkey = geng;//monkey是People对象geng的上转型对象
        geng.crySpeak("20165210");
        People people = (People) monkey;//把上转型对象强制转化为子类的对象
        people.computer(6, 111);
    }
}
